Apparatus for transferring cargo between upper and lower decks of an aircraft. A lift platform receivable in a through opening in the upper deck is raised and lowered by a mechanism using a cable and linear actuator, such as a ball screw. The entirety of the mechanism may be housed in a structure that forms a divider within the aircraft, such as a horizontal deck, vertical bulkhead, or the lift platform itself, thus saving valuable interior volume of the aircraft. Also provided is a recess formed in the lower deck that receives the lift platform. A translating floor assembly mounted in the recess includes transversely extending deck segments that are displaceable between a raised configuration level with the lower deck, and a lowered configuration that clears the recess to receive the lift platform. Installed tracks guide the deck segments between the raised and lowered configurations.
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1. An apparatus for transferring cargo between an upper deck and a lower deck of an aircraft having at least one partition that divides an interior volume of said aircraft, said apparatus comprising:
a lift platform that is receivable in a through opening formed in said upper deck of said aircraft, said lift platform having an upper surface for supporting a load of cargo thereon; and
a lift mechanism that lowers and raising raises said lift platform between said upper deck and said lower deck so as to transfer loads of cargo to and from said upper deck via said through opening, said lift mechanism comprising:
at least one lift cable; and
a drive assembly that selectively extends and retracts said lift cable so as to lower and raise said lift platform;
substantially the entirety of said drive assembly being housed in a structure that is incorporated into said partition so as to minimize intrusion of said drive assembly into said interior volume of said aircraft.
10. An apparatus for transferring cargo between an upper deck and a lower deck of an aircraft, said apparatus comprising:
a lift platform that is receivable in a through opening formed in said upper deck of said aircraft, said lift platform having an upper surface for supporting a load of cargo thereon; and
a lift mechanism that lowers and raises said lift platform between said upper deck and said lower deck so as to transfer loads of cargo to and from said upper deck via said through opening, said lift mechanism comprising:
at least one lift cable; and
a drive assembly that selectively extends and retracts said lift cable, said drive assembly comprising:
an anchor point that retains an end of said at least one lift cable;
at least one ball screw and having a travelling nut in cooperating drive engagement, said travelling nut being located a spaced distance from said anchor point;
at least one pulley mounted to said travelling nut, said lift cable being routed over said pulley from said anchor point; and
a motor that reversibly rotates said ball screw, in a first direction that shortens said distance between said pulley and said anchor point so as to extend said lift cable, and in a second direction that increases said distance between said pulley and said anchor point so as to retract said lift cable.
15. An apparatus for transferring cargo between an upper deck and a lower deck of an aircraft, said apparatus comprising:
a lift platform having an upper surface for supporting a load of cargo thereon;
a drive mechanism that lowers and raises said lift platform between said upper deck and said lower deck so as to transfer loads of cargo to and from said upper deck;
a recess in said lower deck of said aircraft that receives said lift platform therein, so that said upper surface of said lift platform extends substantially flush with an upper surface of said lower deck when said lift platform is lowered therein; and
a translating floor assembly mounted in said lower deck of said aircraft, said translating floor assembly having a raised position which defines a floor surface that extends over said recess generally flush with said upper surface of said lower deck, and a lowered position which clears said recess to receive said lift platform in said lower deck of said aircraft, said translating floor assembly comprising:
at least one collapsible deck section, said collapsible deck section comprising:
at least one generally transversely extending deck segments; and
a translation assembly that displaces said deck segments between a raised configuration in which an upper surface thereof is substantially flush with an upper surface of said lower deck of said aircraft, and a lowered configuration in which said upper surfaces of said deck segment is depressed below said upper surfaces of said lower deck so as to clear said recess to receive said lift platform therein.
2. The apparatus of
a linear actuator operatively connected to said at least one lift cable so as to be selectively extensible and retractable from and into said lift mechanism.
3. The apparatus of
an anchor point that retains an end of said at least one lift cable; and
a pulley mounted to said linear actuator a spaced distance from said anchor point;
said at least one cable being routed over said pulley from said anchor point so that in response to operation of said linear actuator in a first direction that shortens said distance between said pulley and said anchor point said lift cable is extended from said lift mechanism, and in response to operation of the linear actuator in a second direction that increases said distance between said pulley and said anchor point said lift cable is retracted into said lift mechanism.
4. The apparatus of
at least one ball screw and having a travelling nut in cooperating drive engagement, said pulley being mounted to said travelling nut; and
a motor that reversibly rotates said ball screw, in a first direction that shortens said distance between said pulley and said anchor point so as to extend said lift cable, and in a second direction that increases said distance between said pulley and said anchor point so as to retract said lift cable.
5. The apparatus of
6. The apparatus of
7. The apparatus of
8. The apparatus of
a stabilizer assembly that stabilizes said lift platform as said lift platform is lowered and raised between said upper and lower decks of said aircraft.
9. The apparatus of
first and second elongate leg members that are selectively pivotable from a first, horizontal position in which said leg members nest along said lift platform when said lift platform is in a raised and stowed position to a second, vertical position in which said leg members stabilize said lift platform as said lift platform is lowered and raised between said upper and lower decks;
first and second guide members that are mounted to said lift platform in longitudinal sliding engagement with said stabilizer legs.
11. The apparatus of
12. The apparatus of
13. The apparatus of
14. The apparatus of
16. The apparatus of
at least one guide member mounted to said deck segment; and
at least one track member with which said guide member is in cooperating engagement, so that in response to travel of said guide member along said track member said deck segment is guided between said raised and lowered configurations.
17. The apparatus of
guide rollers mounted to sides of said at least one deck segment.
18. The apparatus of
guide channels in which said guide rollers are received for travel therethrough.
19. The apparatus of
first and second generally transversely extending deck segments; and
means for displacing said first and second deck segments between a raised configuration in which said deck segments extend in end-to-end alignment with upper surfaces thereof substantially flush with said upper surface of said lower deck of said aircraft, and a lowered configuration in which said upper surfaces of said deck segments are depressed below said upper surface of said lower deck so as to clear said recess for receiving said lift platform therein.
20. The apparatus of
at least one guide member mounted to each of said first and second deck segments; and
at least first and second track members with which each guide members are
in cooperating engagement, so that in response to travel of said guide members along said track members said deck segments are guided between said raised and lowered configurations, said track members extending generally inwardly and downwardly from relatively elevated outboard ends to relatively depressed inboard ends, so as to guide said first and second deck segments inwardly and downwardly towards said depressed configuration and upwardly and outwardly towards said raised configuration.
21. The apparatus of
a plurality of rail segments mounted on said at least one deck segments that align with cargo rails on said lower deck of said aircraft when said deck segment is in said raised configuration.
22. The apparatus of
an area of said lower deck of said aircraft in which edges of floor frames have been removed so as to form said recess therein.
23. The apparatus of
24. The apparatus of
guide channels mounted in pairs to said floor frames on opposite sides of said first and second deck segments in said intercostal space between said floor frames.
25. The apparatus of
a plurality of said collapsible deck sections mounted in a plurality of said intercostal spaces over a length of said recess in said lower deck of said aircraft.
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This application is a continuation-in-part application of U.S. Ser. No. 13/199,696 filed 6 Sep. 2011, now abandoned which is a continuation of U.S. Non-Provisional patent application Ser. No. 11/297,020 filed on 7 Dec. 2005, now U.S. Pat. No. 8,011,617 which claims the benefit of U.S. Provisional Patent Application No. 60/691,633 filed on 17 Jun. 2005.
a. Field of the Invention
The present invention relates generally to cargo systems for aircraft, and, more particularly, to systems for transferring and stowing cargo within the interior of an aircraft that allows for efficient and cost-effective conversion of passenger aircraft to cargo service.
b. Related Art
Historically, the commercial aircraft industry has distinguished between passenger and cargo aircraft, i.e., certain aircraft are dedicated to passenger travel while others are used solely for transportation of cargo. However, it is frequently desirable to convert an aircraft, in whole or in part, from one service to the other, the most typical example being an older passenger aircraft converted to cargo service.
A problem presented by such conversions is the difficulty in delivering the palletized cargo to the main (passenger) deck of the aircraft, after this area is cleared of seating. In a passenger aircraft, cargo is ordinarily carried in palletized form in lower deck cargo compartments. Typically, there are compartments fore-and-aft of the wing intersection/wheel well area, with each cargo compartment being serviced by a door on the lower lobe. Various types of ULDs (unit load devices) are carried in the compartments; depending on aircraft type and cargo, the ULDs may have a single line or “two abreast” configuration.
In making a cargo conversion, the ability to carry additional ULDs (as opposed to non-containerized cargo) on the main deck is an attractive option, however, it has heretofore been problematic: Carriage of ULDs on the main deck has historically required adding a large cargo door in the upper part of the fuselage, allowing direct access to the main deck; this is a major structural modification, requiring extensive reinforcement, with associated costs and regulatory approval difficulties that impact feasibility.
An alternative would be to transfer cargo from the lower lobe to the main deck (or to the two upper decks in the case of “double decker” jumbo aircraft), since the lower deck already has a cargo door, thus eliminating the requirement for a new main deck door. However, there has heretofore been a lack of satisfactory mechanisms for transferring ULDs from the lower lobe to the passenger deck/decks and vice versa. Moreover, the installation of such a mechanism, when modifying an existing passenger aircraft, presents the potential for structural and cost problems similar to those involved in installing an upper deck cargo door.
Related problems exist in certain dedicated cargo aircraft, notably double-decker “jumbo” aircraft that have been converted to full-time cargo use. For example, 747 cargo aircraft generally transport cargo on the main deck, that in passenger aircraft would carry seating, but the difficulty in raising cargo to the upper deck in the forward position of the fuselage means that this part of the aircraft frequently goes largely unused.
Accordingly, there exists a need for an apparatus for efficiently transferring cargo ULDs and similar containers between the lower area and upper deck or decks of an aircraft, so as to obviate the need to add a large cargo door in the upper part of the fuselage. Furthermore, there exists a need for such an apparatus that does not require major structural modifications of the aircraft. Still further, there exists a need for such an apparatus that, in itself, is comparatively economical, and that is physically compact so as to avoid significantly compromising the availability of space within the passenger and cargo areas of the aircraft. Still further, there exists a need for such an apparatus that is light in weight and does not require power systems that would add significant weight and cost to the aircraft in which the apparatus is installed. Still further, there exists a need for such an apparatus that operates with sufficient rapidity to avoid adding excessive time to loading/unloading operations and turnaround of the aircraft in service.
The present invention addresses the problems cited above, and provides an apparatus for transferring cargo between an upper deck and a lower deck of an aircraft.
In a broad aspect, the apparatus comprises (i) a lift platform that is a receivable in a through opening in the upper deck of the aircraft, the lift platform having an upper surface for supporting a load of cargo thereon, and (ii) a lift mechanism for lowering and raising the lift platform between the upper deck and the lower deck so as to transfer loads of cargo to and from the upper deck via the through opening, the lift mechanism comprising at least one lift cable and a drive assembly that selectively extends and retracts the lift cable so as to lower and raise the lift platform, substantially the entirety of the drive assembly being housed in a structure that forms a divider within the aircraft.
The drive assembly may comprise a linear actuator operatively connected to the at least one lift cable so as to be selectively extensible and retractable from and into the lift mechanism. The drive assembly may further comprise an anchor point that retains an end of the at least one lift cable, and a pulley mounted to the linear actuator a spaced distance from the anchor point, the at least one cable being routed over the pulley from the anchor point so that in response to operation of the linear actuator in a first direction that shortens the distance between the pulley and the anchor point the lift cable is extended from the lift mechanism, and in response to operation of the linear actuator in a second direction that increases the distance between the pulley and the anchor point the lift cable is retracted into the lift mechanism. The linear actuator may comprise at least one ball screw having a travelling nut in cooperating drive engagement, the pulley being mounted to the travelling nut, and a motor for reversibly rotating the ball screw, in a first direction that shortens the distance between the pulley and the anchor point so as to extend the lift cable, and in a second direction that increases the distance between the pulley and the anchor point so as to retract the lift cable.
The drive assembly may be mounted so that the linear actuator extends generally parallel to a main plane of the divider that is formed by the structure within the aircraft. The structure in which the drive assembly is housed may comprise the lift platform that is receivable in the opening in the upper deck of the aircraft, a generally horizontal deck of the aircraft, or a generally vertical bulkhead of the aircraft.
The apparatus may further comprise means for stabilizing the lift platform as the lift platform is lowered and raised between the upper and lower decks of the aircraft. The means for stabilizing the lift platform may comprise first and second elongate leg members that are selectively pivotable from a first, horizontal position in which the leg members nest along the lift platform when the lift platform is in a raised and stowed position to a second, vertical position in which the leg members stabilize the lift platform as the lift platform is lowered and raised between the upper and lower decks, and first and second guide members that are mounted to the lift platform in longitudinal sliding engagement with the first and second leg members.
The invention further provides an apparatus for transferring cargo between an upper deck and a lower deck of an aircraft, comprising a lift platform that is receivable in a through opening formed in the upper deck of the aircraft, the lift platform having an upper surface for supporting a load of cargo thereon, and a lift mechanism for lowering and raising the lift platform between the upper deck and the lower deck so as to transfer loads of cargo to and from the upper deck via the through opening, the lift mechanism comprising at least one lift cable and a drive assembly that selectively extends and retracts the lift cable, the drive assembly comprising an anchor point that retains an end of the at least one lift cable, at least one ball screw having a travelling nut in cooperating drive engagement, the travelling nut being located a spaced distance from the anchor point, at least one pulley mounted to the nut, the lift cable being routed over the pulley from the anchor point, and a motor for reversibly rotating the ball screw, in a first direction that shortens the distance between the pulley and the anchor point so as to extend the lift cable, and in a second direction that increases the distance between the pulley and the anchor point so as to retract the lift cable. The drive assembly may be housed substantially entirely within a structure that forms a divider in the aircraft. The structure in which the drive assembly is housed may comprise the lift platform that is receivable in the through opening in the upper deck of the aircraft, a generally horizontal deck of the aircraft, or a generally vertical bulkhead of the aircraft.
The invention further provides an apparatus for transferring cargo between an upper deck and a lower deck of an aircraft, comprising a lift platform that is receivable in a through opening formed in the upper deck of the aircraft, the lift platform having an upper surface for supporting a load of cargo thereon, means for lowering and raising the lift platform between the upper deck and the lower deck so as to transfer loads of cargo to and from the upper deck via the through opening, and a recess in the lower deck of the aircraft for receiving the lift platform therein so that an upper surface of the lift platform extends substantially flush with an upper surface of the lower deck when the lift platform is lowered therein.
The apparatus may further comprise a translating floor assembly mounted in the lower deck of the aircraft, the translating floor assembly having a first position which defines a floor surface that extends over the recess generally flush with the upper surface of the lower deck, and a second position which clears the recess for receiving the lift platform in the lower deck of the aircraft.
The translating floor assembly may comprise at least one collapsible deck section, the collapsible deck section comprising at least one generally transversely extending deck segment, and means for displacing at least one deck segment between a raised configuration in which an upper surface therefore is substantially flush with the upper surface of the lower deck of the aircraft and lowered configuration which the upper surface of the deck segment is depressed below the upper surface of the lower deck so as to clear the recess for receiving the lift platform therein.
The means for displacing the at least one deck segment may comprise at least one guide member mounted to the deck segment, and at least one track member in which the guide member is in cooperating engagement, so that in response to travel of the guide member along the track member the deck segment is guided between the raised and lowered configurations. The at least one guide member may comprise guide rollers mounted to sides of the at least one deck segment, and the at least one track member may comprise guide channels in which the guide rollers are received for travel therethrough.
The at least one collapsible deck section may comprise first and second transversely extending deck segments, and means for displacing of the first and second deck segments between a raised configuration in which the deck segments extend in an end-to-end alignment with upper surfaces thereof substantially flush with the upper surface of the lower deck of the aircraft, and in lowered configuration in which the upper surfaces of the deck segments are depressed below the upper surface of the lower deck so as to clear the recess for receiving the lift platform thereof. The means for displacing the first and second deck segments may comprise at least one guide member mounted to each of the first and second deck segments, and at least first and second track members with which the guide members are in cooperating engagement, so that in response to travel of the guide members along the track members the deck segments are guided between the raised and lowered configurations, the track members extending inwardly and downwardly from relatively elevated outboard ends to relatively depressed inboard ends so as to guide the first and second deck segments inwardly and downwardly towards the depressed configuration and upwardly and outwardly towards the raised configuration.
The collapsible deck section may further comprise a plurality of rail segments mounted on the at least one deck segment that align with cargo rails on the lower deck of the aircraft when the deck segment is in the raised configuration.
The recess in the lower deck of the aircraft may comprise an area of the lower deck of the aircraft in which edges of floor frames have been removed so as to form the recess therein. The translating floor assembly may be mounted in an intercostal space intermediate the floor frames of the lower deck of the aircraft, and the guide channels may be mounted in pairs to the floor frames on opposite sides of the first and second deck segments in the intercostal space between the floor frames.
The translating floor assembly may comprise a plurality of the collapsible deck sections mounted in a plurality of intercostal spaces over a length of the recess in the lower deck of the aircraft.
These and other features and advantages of the present invention will be more fully understood and appreciated from a reading of the following detailed description with reference to the accompanying drawings.
As used in this description and the appended claims, the term “lower deck” refers to a first deck on which cargo is positioned, and the term “upper deck” refers to a second deck above the first, to and/or from which the cargo is transferred by the lift apparatus of the present invention. One may be a dedicated cargo deck and the other primarily a passenger deck, as shown in
Accordingly,
As can be seen, the lift assembly 12 includes a lift platform 30 that is received within an opening in the main deck 18, so that when stowed the lift platform is incorporated into the latter with its upper surface lying generally flush with that of the deck so as to form a more-or-less uninterrupted load surface; as used herein with respect to the lift platform, the term “upper surface” refers to the upper, load-bearing side of the platform, which preferably has a generally flat, horizontal aspect so as to correspond to the surrounding deck of the aircraft, but which may or may not be continuous and may include various projections such as tracks, rollers, tie-downs, housings and so on as well as depressions, openings, and various structural features. As will be described in greater detail below, the mechanism of the lift apparatus allows it to be housed substantially in the lift platform itself to form an essentially self-contained unit, or within the space of the adjoining deck, bulkhead or other partition that divides an interior volume of the aircraft, so that the mechanism is incorporated into the partition to minimize intrusion and the interior volume of the aircraft is not significantly diminished or compromised when the apparatus is installed. Moreover, when in the stowed position, the lift platform preferably attaches structurally to the main deck 18 so as to form a load-bearing component thereof, so that the structural impact to the aircraft (from its unmodified condition) is minimal. As will also be described in greater detail below, a cut-out 32 may be formed in the floor of the cargo deck 16 to receive the platform when it is in the lowered position, and the cutout may be spanned by removable tracks 34 or track segments on drop-down floor structures when the lift platform is stowed in the raised position.
To prepare the upper lobe for cargo use, all or a selected number of seats 20 are removed and a divider panel 36 is installed between the cargo area and any remaining passenger areas of the upper deck. In the lower lobe, in turn, the tracks 34 may be removed so that the lift platform 30 can be lowered to position in which its upper surface is flush with that of the cargo deck 16, as shown in
The ULDs can thus be loaded/unloaded in the lower lobe through the main loading door (not shown) with which the aircraft was originally equipped. The ULDs/pallets are then moved longitudinally through the hold on tracks (not shown) on deck 16, which again may be an original part of the aircraft. The upper surface of the lift platform 30 may be provided with corresponding track segments that align with those on the cargo deck when the lift is in the lowered position, so that the ULDs 14 can be transported thereover, e.g., to the position of the right-most ULD in
With a ULD in position on the lift platform, the internal mechanism of the platform is actuated to raise/lower the ULD through the opening 38 in the main deck, in the manner shown in
As shown, the lift assembly is preferably installed in the aft portion of the aircraft, but forward of the rear passenger door. Positioning the lift forward of the door avoids a “log jam” situation that could interfere with traffic flow, while rearwardly of the door the fuselage typically tapers in a manner that would impose impractical geometry and space restrictions. Furthermore, the barrier panel can be positioned as far forward as desired, so as to avoid separating any remaining passenger area from the crew spaces or from the main passenger-loading door at the front of the aircraft. It will be understood, however, that the lift assembly may be installed in other locations as desired.
Since in the illustrated embodiment the lifting and stabilizing mechanisms are all contained within the lift platform and the associated deck opening, very little modification of the aircraft is required to install the system. The main modification is to cut the through opening in the passenger deck 18; as is described in greater detail below, the lift deck is preferably tied structurally to the main deck when in the stowed position, so that there is virtually no loss or compromise of structural integrity due to the opening 38. The receiver opening 32 in the lower deck also does not significantly affect structural integrity, since the portion of the frames that is removed does not serve a structural purpose with respect to the aircraft body and is only provided to support the overlying floor surface. Finally, power requirements are met by simply connecting an electrical cable to the platform, to supply electrical power to the motor that is housed therein.
The through opening 38 in the deck itself is suitably formed by cutting an area out of the floor and deck support beams 36, and then installing headers 48 that join the severed beam ends to the uncut beams at the forward and rearward ends of the opening. Locking mechanisms 50 are mounted at the inboard sides of the headers, at the location of each cut beam, for forming a structural engagement between the platform and the deck, as will be described in greater detail below.
The lower opening 32, in turn, can be formed by cutting down the upper edges of corresponding floor frames 52, to a height that generally matches that of the lift platform 30 so that the upper surface of the latter will be level with the floor of the cargo deck 18 when the platform is in the lowered position; as noted above, this does not compromise the structural integrity of the aircraft, since the upper edges of the floor frames only support the floor panels and tracks of the cargo compartment rather than serving a load carrying function with respect to the fuselage. Tracks 54 are mounted to the cargo deck floor and align with the removable track segments when the latter are in place.
As can be seen in
The frame 60 is substantially rectangular in outline, with longitudinally-extending side beams 66 that are joined by a series of transverse beams 68; as can be seen in
As can be seen with further reference to
As can be seen in
The scissors-action mechanisms on the two sides of the lift platform stabilize the lift platform against side-to-side and fore-to-aft motions as it is being raised/lowered, as well as against tipping/tilting forces caused by the load. The rigid members are formed of any suitable rigid, high strength material, such as steel or aluminum, and are suitably tapered as shown, in the interest of minimizing weight.
The actual raising/lowering of the lift platform is accomplished by means of cables that are attached to the pulley mechanism 70. As can be seen in
As can be seen in FIGS. 12 and 17-19, the actuating mechanism 70 includes twin ball screws 102a, 102b that span the distance between the two side beams of the frame, the ball screws being driven by an electric motor 104 and reduction gear 106. A paired travelling nut 108 is in threaded engagement with both ball screws, and supports pulley set 110 on a common shaft that extends transversely between the individual traveling nuts 112a, 112b. Rotation of the screws by the motor and reduction gear selectively moves the paired traveling nut in one direction or the other (i.e., towards one end or the other), depending on the direction of rotation of the motor. The base ends of the cables are mounted to anchor points on a plate 114 on the frame member 66 at one end of the actuating mechanism, from which the cables are routed over the pulleys carried on the travelling ball nuts so that the cables are paid out or retracted as the travelling nuts move one way or the other. Additional pulleys redirect the cables in a vertical direction, with the distal ends of the cables being mounted to the stationary deck beam as noted above. The end plate 114 also carries the bearings 116a, 116b that support the distal ends of the ball screws.
The ball screw mechanism employed in the illustrated embodiment possesses significant advantages, notably in terms of low-friction and the ability to withstand high thrust/loads, however, it will be understood that other screw-type and non-screw type linear actuators may be used to extend/retract the pulley or pulleys in some embodiments, such as roller-screw actuators, jack-screw actuators, hydraulic actuators, telescoping actuators and pneumatic actuators, for example. An important aspect of linear actuators with respect to the present invention is that the generally axial geometry of the mechanism (as compared with a winch drum, for example) reduces bulk in the other dimensions, which as described below enables it to be mounted with the axis parallel to the main plane of a deck or other divider structure so as to be housed entirely within the confines of the structure and therefore avoid impinging on the interior volume of the aircraft.
As can be seen, the pulley set 110 that is carried on the pair of travelling nuts includes first and second paired, stepped pulley units 120a, 120b. The cables are led in pairs —100a, 100b and 100c, 100d—from the base plate 114, longitudinally (i.e., parallel to the ball screws) over the two stepped pulley units 120a, 120b, and then in reverse direction back towards the base plate. The cable pairs are redirected in a horizontal direction outwardly from the actuating mechanism by a set of vertical-axis stepped pulleys 122a, 122b, and are then redirected into vertical legs by horizontal-axis stepped pulley units 124a, 124b; a second vertical-axis stepped pulley unit 126 is used to lead cables 100a, 100b to the opposite end of the assembly, but is not required for the other cable pair 100c, 100d. The stepped pulley sets serve to ensure equal travel of the cables, i.e., the cables are routed over the larger- and smaller-diameter pulleys in each set so that the travel is the same despite the offset distance between the cables in each pair 100a, 100b and 100c, 100d.
Accordingly, actuating the motor in a first direction so as to cause the travelling nut assembly to move towards the motor (i.e., to the left, as shown in
The preferred actuating system that is shown in the figures provides a 2:1 ratio of platform movement to pulley movement, which is a significant factor allowing the actuation system to be nested laterally within the platform.
Use of twin ball screws prevents eccentric loading on the travelling nuts should a cable fail; the load on a single ball screw may increase but there would not be any induced bending. The use of multiple cables also provides a degree of redundancy and added safety; the cables are preferably sized so that any single cable is capable of supporting the platform against falling in the event that the other cables are damaged or fail. Moreover, use of cables on two sides of the platform rather than at a single attachment point reduces torsion and bending loads during operation of the system.
The power requirements of the electrical motor 104 are easily met by either ground or onboard (aircraft) sources, supplied to the motor by an electrical cable as described above.
It will be appreciated that the geometry and dimensions of the lift mechanism that allow it to be housed within the confines of the lift platform similarly enable it to be mounted within the confines of a deck having a somewhat corresponding structure and interior height. For example,
In the embodiment that is illustrated in
As can be seen with further reference to
It will be understood that while in
As can be seen more clearly in
As the lift platform is lowered, the distance shortens between the fixed and moving pivot points 84, 86 and 90, 92, at the upper and lower ends of the scissors-action mechanism, as shown in
Each of the guide assemblies in the illustrated embodiment includes a stationary, parallel pair of T-shaped (in cross section) rails 140 that are received in corresponding parallel channels in sliding bracket members 144, so that the latter are free to slide in a horizontal direction while being supported vertically. The pin 92 that forms the lower sliding pivot is mounted to a downwardly projecting portion of the outboard, lower sliding bracket member, while the pivot pin of the upper pivot joint is mounted to the upper sliding bracket member. As can be seen in
The guide rails 142 and/or the channel portions in which they are received may be formed of metal, provided with suitable lubrication. In some embodiments, however, either or both may be formed of a polymeric material having low friction and self-lubricating characteristics combined with strength and durability, such as Delrin™, for example.
Linear guide assemblies that have been described above have the advantages of compactness, durability and ease of maintenance. It will be understood, however, that other types of linear guide mechanisms known to those skilled in the relevant art may be employed in other embodiments of the invention.
As noted above, the cargo lift system of the present invention can be installed without significantly affecting the structural integrity and load capacity of the aircraft, and of the main passenger deck in particular, due to the lift platform in effect becoming an integral part of the deck structure when in the up/stowed position. This is a very significant advantage since, in addition to the general loading due to passengers or cargo, the floor beams of the passenger deck carry significant lateral load in a pressurized aircraft. Consequently, it is desirable to maintain lateral continuity in the deck in order to ensure minimal changes to the fuselage loads during flight.
As can be seen in
As can be seen in
The receivers 152 engage locking pins or lugs 160 that are mounted to the side beams 66 of the lift platform 30. As can be seen in
As can be seen in
Once the pin member 160 has entered the receptacle area of the latching member, as shown in
Accordingly, when the latches are in the locked position, loads are transferred directly from the truncated deck beams to the transverse beams of the platform, by the shaft portions of the latch mechanisms, so that lateral and vertical load carrying capabilities are preserved intact as compared with the unmodified floor structure. The spherical pin design provides lateral and vertical restraint while permitting limited rotation, thus reducing component size and strength requirements. It will be understood that the orientation of the components may be reversed from those that are shown, i.e., the pins in the cam latches can be mounted on either the platform or the passenger deck, depending on design factors.
The latch mechanism described with reference with
Accordingly,
The lift apparatus 210 is broadly similar to that of the embodiment described above, in that it likewise utilizes a lift platform 220 that houses a substantially self-contained operating mechanism, and that mounts structurally to the upper deck when in the raised, stowed position. However, the lift and stabilization mechanisms are configured to accommodate the larger loads anticipated in a wide-body “jumbo” aircraft, as well as the greater height between decks and other differences in geometry. The lift platform 220 therefore lowers and raises between the upper and main decks 214, 204 of the aircraft, transferring ULDs 212 to/from the upper deck via the through opening 228. As was also described above, a divider panel 230 may be provided on the upper deck to section off the cargo space from other interior areas.
As can be seen in
Thus, operating the motor 236 so as to pay out the cable pairs lowers the lift platform from the upper deck to the main deck as described above, while operating it in the reverse direction raises the platform back to the upper deck. The platform has an inherent degree of stability due to the location of the four cable pairs 222a-222d at its corners. Moreover, because each cable (which is suitably a synthetic fiber rope, as described above) is paired with a mate, a degree of redundancy is ensured in the event that any single cable should fail.
While the doubled-up arrangement of paired ball screw mechanisms thus provides significant advantages for certain applications, it will be understood that some embodiments may employ a single paired ball screw mechanism similar to that described above, in the interest of simplicity or economy for example, or even a single non-paired ball screw and nut; conversely, additional paired or un-paired ball screw mechanisms and associated drive motors may be used in some embodiments. Moreover, although attaching the cables at the sides of the lift platform/opening provides significant advantages in terms of stability and clearance for movement onto/off of the platform, it will be understood that in some instances the cables may be attached at the forward/aft ends of the platform instead of or in addition to the ends.
Prior to actuation of the lift platform, however, the guide legs pivot downwardly, as indicated by arrows 254, passing progressively through positions 224a′-b′ and 224a″-b″, until reaching vertical alignment at position 224a′″-b′″. At vertical alignment, pin portions 256 on the distal ends of the legs enter sockets in receivers 256a-b on the main deck, so as to temporarily lock the guide legs in a vertical position.
As can be seen more clearly in
When the lift platform 220 is in its raised position, the guide blocks 226a-b are accommodated within downward facing openings 268 of receivers 270 mounted to the upper deck (see
In operation, the guide legs 224a-b are first deployed to their vertical orientation, with the pins on the lower ends of the legs being locked in the lower receivers 256a-b. The drive mechanism 232 of the lift platform is then actuated to lower and raise the platform, with the guide blocks 226a-b sliding along the vertical legs to stabilize the platform against motion in a side-to-side or front-to-rear direction.
As was noted above, a cutout in the underlying floor receives the lift platform when the latter is in its lowered position; when the platform has been raised and stowed, a pair of rails may be set across the cutout to span the opening. However, removing and replacing the rails involves a degree of delay, and moreover, this approach may not be satisfactory under circumstances where a more continuous floor surface is required.
The first figure,
As can be seen in
As can be seen in
Raising and lowering of the section is accomplished, in the illustrated embodiment, by means of a pair of actuator segments 310a, 310b. As can be seen in
Rotation of the torque tubes (in a clockwise direction as seen in
The torque tubes may be rotated by one or more motors (not shown) or other suitable drive devices. Rotation of the torque tubes is preferably linked so that all of the sections in the floor assembly 294 rise/fall simultaneously with minimal delay.
As can be seen with further reference to
Each pair of guide channels follows a contour such that they cooperate with the respective rollers to guide and direct motion of the deck segments as the latter are lowered/raised, as will be described in greater detail below: The guide channels 402a-b at the base end of the first deck segment 382 have a somewhat level upper portion 414 that transitions through a bend to a roughly 45° inwardly and downwardly sloped middle portion 416, that in turn transitions through an outward bend to a more shallowly sloped (e.g., roughly 30°) inner/lower portion 418; the distally located pair of channels 404a include a somewhat vertically aligned upper portion 420 that transitions through a U-shaped bend to a generally horizontal lower/inner portion 422. The base-end guide channels 406a-b of the second, shorter deck segment 384 in turn have generally horizontally sloped upper/outer portions 424 that transition through downward bends to outwardly sloped (e.g., roughly 45°) middle portions 426, that in turn transition through outward bends to more shallowly sloped lower inner portions 428; the distal set of channels 408a-b include generally vertical upper portions 430 that transition through inward bends to generally horizontal middle portions 432, that in turn transition to relatively gently downwardly sloped (roughly 30°) lower portions 434 that terminate at slightly upturned, somewhat horizontal end portions 436.
The guide channels are suitably formed of a metallic or non-metallic material having sufficient strength and rigidity to contain and guide the guide members while supporting the weight of the deck segments, such as aluminum, steel or molded composite material, for example. In addition to the rollers that are illustrated, other guide members that may be used with the guide channels include, for example, guide pins and guide blocks, preferably formed of a low-friction material such as Delrin™. Moreover, in some embodiments the guide members may be formed with channels or grooves in which guide tracks are received, that cooperate to support and guide the deck segments in a manner similar to the guide rollers and channel-type guide tracks that are illustrated. It will also be understood that the number and path configurations of the track members may vary somewhat from those shown, depending on spacing, available height/width, and other design factors.
The manner in which the guide roller and channels cooperate to direct movement of the deck segments is illustrated by a comparison of the assembly in the raised configuration shown in FIGS. 39 and 41-42, with the lowered configuration shown in FIGS. 40 and 43-44. As can be seen therein, to transition from the raised to the lowered configuration, the ends 440, 442 of the deck segments 382, 384 separate at junction 388, and the shorter segment 384 is first lowered toward the bottom of the fuselage area lying below the level of deck beams 398. In so doing, the distal set of guide rollers drop vertically through the upper portions 430 of channels 408a-b, while the set of rollers at the base end of the deck segment pivot in the upper portions 424 of channels 406a-b and move somewhat forwardly therethrough to accommodate the downward motion of the distal rollers. As the base set of rollers reach the bends at the bottom of upper portions 430 and move into the sloped middle portions 432 of channels 408a-b, the distal set of rollers simultaneously move forward through the upper portions 424 of channels 406a-b and then enter sloped portions 426, so that the deck segment shifts in a downward and inward direction. As the distal set of rollers enter the more steeply sloped lower portions 434 of channels 408a-b, the base set of rollers pivot in the lower portions 428 of channels 406a-b, allowing the end 442 of the deck segment to descend towards the bottom of the fuselage, and as the rollers reach end points 436 the depressed elevation of the latter relative to the corresponding end points of channels 406a-b angles the bottom of the deck segment to roughly follow and fit closely within the curved fuselage shell 386.
After the shorter deck segment 384 has been lowered into, or close to, the position shown in FIGS. 40 and 43-44, the longer deck segment 382 is lowered in its turn. As can be seen by comparison of
Thus lowered, the assembly 380 clears a depression 444 in the lower cargo deck of the aircraft that accommodates a lift platform, so that the latter can be lowered into a position level with the cargo deck in a manner similar to that described above. Then, when the assembly is in the raised configuration, the rail segments 394 extend level and continuous with the installed rails of the cargo deck so that pallets/cargo can be moved thereover in a normal manner. The deck segments of the translating deck assembly may be lowered and raised manually, or power may be supplied by an electric or hydraulic motor or other source. The segments may be locked in the raised configuration, for example by passing locking pins (not shown) through members 398a-b and 392a-b into the adjoining fixed deck beams 398, or by other suitable locking devices.
The translating floor assemblies thus allow the lift assembly to be used with no reduction in allowable floor space in the aircraft. The embodiments that have been described with reference to
It is therefore to be recognized that these and various other alterations, modifications, and/or additions may be introduced into the constructions and arrangements of parts described above without departing from the spirit or ambit of the present invention as defined by the appended claims.
Curry, James M., Schemkes, Randolph
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